Improvement in millstone-dress



UNITED STATES PATENT OEEICE.

DAVID IV. THOMPSON, OF SOMERSET, PENNSYLVANIA.

IMPROVEMENT IN MILLSTONE-DPLESS.

Specification forming part of Letters Patent No. 44,47 l dated September 27, 1864.

To all whom it may concern Be it known that I, DAVID W. THOMPSON, of the town of Somerset, in the county ot' Somerset and State of Pennsylvania, have invented a new and useful Improvement in Dressing Millstones and I do hereby declare that the following is a full, clear, and exact description of the construction and operation of the same, reference being had to the accompanying drawings, making-part of this specitication, in which- Figure 1 is a plan view of a runner with my dress applied; and Fig. 2, a plan view of the bed-stone, showing my invention.

Various modes of giving a proper ventila tion between millstones have been attempted; lout none to my knowledge were properly et'- fective before my invention, which consists in surrounding the eye of the runner with an annular-grooved space cut at nearly a central distance from the axis in the face ofthe stone, when the bed-stone, also, is dressed with an annular' groove of the same diameter as that in the runner and parallel therewith, both annular grooves intersecting the leading furrows ofthe dress.

In the known modes of dressing millstones it is found almost impossible to cause the grain fed to the stone to be so equally distributed that all the furrows shall share equally in the work performed 5 and my invention further consists in the combination of the annular grooves in the runner and bed stones with the leadinggrooves of any dress, when intersected as described to eii'ect a Inore even and uniform distribution of the grain, so as to en tble each furrow to perform its just proportion ot' the work.

In the accompanying drawings my invention is shown as applied to a pair of four-foot stones, the scale being one inch to the foot. The annular groove A in the runner, Fig. 1, ot' a stone of this size is situated nearly a foot fiom the axis of the stone, and is about one inch in Width and of any proper depth to give the required ventilation. From the inside of the annular groove to the eye of the stone the surface D is dished to a depth suitable to permit the entrance of the grain between the stones. The outside of the annular groove Op is in a plane surface save where furrowed In radial lines for the usual dress, which divides the whole surface of the stone into furrows and lands. The bedestone, Fig. 2, has its annular groove D situated at the same distance from its axis as that of the annular groove in the runner, and is of the same width, so that the one shall rotate precisely over the other, but its depth is only that of the furrows in the dress. The surface E of the bed-stone is in a plane, with no other depression than that of the furrows which constitute the ordinary dress, its whole surface bein g divided between grooves and lands. The leadingfurrows of both stones cross their annular grooves at different angles, there being nine leading furrows in the ruimer while there are but eight in the bed-stone, as shown in the drawings. The radial furrows from the leading ones vary in width as do the lands,and in the drawings a variety of sectional dresses are shown; but all are well adapted to myimprovement, which may also advantageously be used with other forms of dress or modes of arranging the lands and furrows in both the runner and bed-stone.

In operation, the annular groove in the runner carries so large a quantity ot' air as to give ample ventilation to the stones and cause theI ground Hour or meal to be delivered in a cooler and more perfectly disintegrated condition than has hitherto been possible, while theintersection of the leadingfurrows with the annular grooves causes each to receive therefrom an equal or nearly equal supply of the grain fed to the stones, and thus permits the runner always to rotate in a perfectly horizontal plane and both stones to do an equal amount of work in each part, and thus enables the mill to accomplish a larger quantity of work with the same power in a given time, and to make tlour or meal of a much improved quality from the saine stock.

4It is obvious that my invention is applica- 'ble to other grinding millstones than thore DAVID W. THOIWIPSON.

Witnesses:

I, O. KIMMEL, RoEEn'r LAUGII'roN. 

